This study aims to examine Korean progressive acquisition ‘-ko iss-’ of Chinese learners by level and L1 effect. For this, this study consists of Chinese and other learner’s corpus with 13,957 words. The findings are like follows. Firstly, 4 errors of 17 in an original word have ‘resultive’ meaning and 13 errors of 17 have ‘progressive in action’ meaning in the acquisition of Korean progressive acquisition ‘-ko iss-’. Secondly, the errors of Chinese and other L1 learners in the ‘-ko iss-’ obligatory texts do not reveal any statistical significance. Only Chinese learners, however, have 5 misform errors in the progressive acquisition. Thirdly, the ratio of errors decreased in Chinese learner’s progressive acquisition as the level goes up from low to high. Fourthly, Chinese learners use ‘-ko iss-’ with activity verbs in the low level. As the level goes up, Chinese learners extend ‘-ko iss-’ to accomplishment and achievement verbs; do not extend to psychological verbs. Fifthly, we found 4 counter-examples of Aspect Hypothesis that combine ‘-ko iss-’ with stative verbs. (Yonsei University)